An aircraft refueling boom is a beam fuel-tight unit attached to its forward end to a tanker aircraft having aerodynamic lift surfaces called ruddevators used to aerodynamically control the position of the boom in elevation and azimuth that provides a fuel passage from the tanker to the boom nozzle.
The outer end portion of the boom is a telescoping section for inward and outward movement.
The receiver aircraft is equipped with an aerial refueling receptacle which engages with the boom nozzle for the refueling operation.
The boom operator located in the tanker aircraft guides the boom so as to line the boom nozzle with the receiver aircraft receptacle. When the boom nozzle is aligned with the receiver receptacle the boom operator extends the telescoping portion, so that the nozzle engages the receptacle to complete the coupling which must be accomplished and maintained within a predetermined refueling envelope to avoid a disconnection.
During tanker to receiver contacts, mechanical contact loads are build up and stresses are placed on the boom as well as on the receiver. These stresses can result in boom or receptacle failure.
A boom passive contact loads attenuation mechanism based on a recoil shock absorber on a boom in use is known. One disadvantage of this device is that it is not properly integrated in the boom.
Once the refueling boom is connected to the receiver aircraft, known contact detection systems are based on coil signals installed on the nozzle. One disadvantage of this passive coil signals are the maintenance needs of the coil equipment. Another disadvantage is the potential for damage to the coil since the refueling boom adjacent to the coil installation commonly contacts the receiver aircraft.
Known refueling booms do not provide for automatic boom load alleviation when the refueling boom is connected to the receiver aircraft. Stresses are placed on a boom due to the motion of the tanker as well as from the receiver that can result in boom failure. In these systems it is the responsibility of the boom operator to avoid boom deflections.
A boom load alleviation system employing strain gauges is known. This load alleviation system relies on electrical feedback from the strain gauges to a computer onboard the aircraft which identifies a boom bending load. One disadvantage of this strain gauge type load alleviation system is the routing of the analog signals from the boom tip to the aircraft on board computer as well as the integrity of the raw signals.
The present invention is intended to solve said disadvantages.